Connection failover allows a client application to switch
to an alternate Adaptive Server if the primary server becomes unavailable
due to an unplanned event, like power outage or a socket failure.
In a cluster environment, client applications can fail over numerous
times to multiple servers using dynamic failover addresses.
With high availability enabled, the client application does not need to be configured to know the
possible failover targets. Adaptive Server keeps the client updated with the best
failover list based on cluster membership, logical cluster usage, and load distribution.
During failover, the client refers to the ordered failover list while attempting to
reconnect. If the driver successfully connects to a server, the driver internally
updates the list of host values based on the list returned. Otherwise, the driver throws
a connection failure exception.
Note: The connection properties
DEFAULT_QUERY_TIMEOUT and
INTERNAL_QUERY_TIMEOUT or
DriverManager.setLoginTimeout(xx) play vital role to switch
over from failed node to highly available node after failover occurs.